Generally comfort systems are controlled by a wall mounted thermostat. A modern wall mounted thermostat typically includes a display and a key pad including user buttons for programming the thermostat or for manually adjusting the air temperature in a space for which the thermostat controls the comfort levels. The wiring used to connect thermostats to corresponding heating, ventilation, and air conditioning (HVAC) plants varies between installations. For example, in some legacy home installations, such as those designed for the classic round thermostats, two wires were generally installed between the thermostat and a furnace. By contrast, many modern HVAC plants include a single or multi stage heating system, a humidifier, a fan control, and a single or multi stage air conditioner. Such modern installations can require up to 11 wires or more to establish full control between a digital wall mounted thermostat and the HVAC plant. In many cases, an installer upgrading a thermostat or an HVAC plant or both, has to also install new wiring between the wall where a new thermostat is to be installed and the location of the HVAC plant. In some cases, where it is only desired to upgrade the thermostat, many persons go without a thermostat upgrade merely because it is impractical to install a new multi-wire thermostat control cable.
Modern wall thermostats having significant functionality including time programmable set points, auto change over between heating and cooling, as well as built in humidity control, are presently available. Such relative complexity has been made possible both by microcomputers and the miniaturization of electronics parts in general. Yet, especially the more complex thermostats tend to fill a physical form factor that typically extends from over 1.5″ to 3″ out from the wall. It is not uncommon in either home or commercial settings for a person walking by such a wall mounted thermostat to accidentally come in contact with it. It can also be less aesthetically pleasing in some cases for a wall mounted thermostat to be so visually prevalent in some settings.
What is needed is a thermostat that can provide sufficient control for multiple features of an HVAC plant without requiring the replacement of an existing thermostat control cable running between a thermostat wall mount location and the HVAC plant. Also, what is required is a more aesthetically pleasing thermostat occupying a smaller visual presence as a wall mounted unit.